Recently Superman learnt what it was like to be unpowered, by expending all of his stored Solar energy in one explosive release.
Boom.
There was a crater, and he was naked.
Why detonate himself wearing clothing?
Clark must have spent a lot of time nude out doors, while he was sorting this new super ability out, and maybe he figured out that he liked the life of a natrualist?
Didn't Kara use the solar flare in an episode?